09-16-2016, 06:21 PM
I'm certainly no expert on tubing strength but at only 300-350lbs you should be fine either way with 1/8" thick square tubing. My 2-ton cherry picker has 1/8" thick 2 1/4" square tubing for the arm that bears all of the weight so you should have plenty of overkill. I like overkill myself.
Ed
Ed